Tripods are frequently employed as stable supports for cameras of various types. The camera is typically mounted upon an intermediate platform incorporating means for leveling the camera and for directing the camera vertically and horizontally.
For action pictures, it is frequently necessary to follow the action or the intended subject with the camera until the desired action occurs or until circumstances are right for a good picture. When the brief moment occurs for a particularly good shot, the camera must be in the proper position, and the finger must be on the shutter release, or the opportunity is lost forever.
Prior art means for directing the camera under such circumstances are basically of two types. One type employs a ball and socket arrangement; the other incorporates separate adjustments about three axes.
The ball and socket type, in unlocked mode, provides freedom for rapid directional changes in elevation or in pan (left and right) as needed for tracking a diagonally moving subject, but it also frees the camera to tilt inadvertently out of level, and to switch from locked down to tracking mode, one or two levers must be unlocked manually.
In the type of mechanism incorporating the three separate adjustments, the camera is leveled once and is locked into the leveled position by means of a hand-tightened brake. To switch from a locked down camera position to tracking a diagonally moving subject, however, both the elevation and pan control levers must be unlocked manually.
For a measure of smooth camera motion while panning, a controlled resistance is provided in some movie camera mounts to reduce erratic rate of rotation about the two axes, which results in a noticeably rough transition. The resistance may be provided by causing oil to be forced through a small hole as the platform is rotated, or by using frictional plates in contact with each other.
The difficulty with such prior art arrangements when used for action photography arises from the need for numerous, virtually simultaneous adjustments and operations. In order to manipulate the control knobs or levers associated with the individual directional axes, the photographer must release a hand from its hold on the lens barrel, camera body or grip and move it to the knob or lock lever on the tripod head. In the case of a still photographer shooting an erratically moving subject (children, animals, sports), either the left hand must be removed from the lens barrel (interrupting focus and aperture adjustments) or the right hand must be removed from the shutter trigger. Under certain circumstances, it might be desirable to have the camera locked into position, but if it suddenly becomes necessary to track a moving subject, the situation then calls for a rapid succession of adjustments including the unlocking of the directional axes, last minute focus and framing (composition) readjustments and the timely operation of the shutter trigger.
Physical control of the camera in conjunction with one of the foregoing camera mounts is aided by means of a handgrip on an arm projecting some distance from the camera head. The hand grip is used for directing the camera. A shutter trigger is sometimes incorporated on the handgrip for additional convenience.
While such features have provided some relief from the difficulties described earlier, inconvenience and time delay involved in the locking and unlocking of the pan and elevation brakes remains, affecting performance.